Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 3: Microstructure and Phase Transformations
MM 3.3: Vortrag
Montag, 16. März 2015, 10:45–11:00, H 0106
Ab initio interpretation of the abnormal carbon redistribution during martensitic transformation in Fe-C alloys — •Xie Zhang1,2, Tilmann Hickel1, Jutta Rogal2, Ralf Drautz2, and Joerg Neugebauer1 — 1Max-Planck-Insitut für Eisenforschung GmbH, Düesseldorf, Germany — 2ICAMS, Ruhr-Universität Bochum, Bochum, Germany
As a key feature of the martensitic transformation in Fe-C alloys, the abnormally low tetragonality resulting from the C redistribution is a historically pending problem. To address this issue, we developed an atomistic model for the martensitic transformation in Fe-C alloys and calculated the corresponding minimum energy paths with ab initio nudged elastic band simulations. Our insights provide a theoretical evidence for the C redistribution into different octahedral sublattices in martensite, and thus nicely explain the occurrence of the abnormally low tetragonality. It also allows us to interpret the mechanism for the martensitic transition as a combination of a tetragonal cell deformation and atomic shuffling and thus our understanding of the microstructure evolution in steels.